Display screen or portion thereof with a graphical user interface



The FIGURE is a front view of a display screen or portion thereof with agraphical user interface.

All text is shown in broken lines. The broken lines showing a displayscreen or portion thereof, text, and portions of the graphical userinterface form no part of the claimed design.

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface, as shown and described. 